We could use weechat’sshortcuts to do underline, bold, and colors.
And we could use something like
<code=bash>elinks -dump -dump-color-mode 2
to parse the html and css.
We just then need to convert the Shell colors (^[0;30m etc) to ncurses colors, and there you go.
Running elinks for every xhtml-im message received may be too much?